Hackers have infiltrated a regional Cabinet Office Web site and posted a message in Chinese denouncing Prime Minister Junichiro Koizumi's recent visit to Tokyo's Yasukuni Shrine, police said Wednesday.
"History cannot be altered just like that," the message read under a Chinese flag, according to the police.
It was posted on the site for the Okinawa General Bureau's office for roads (www.north-road.go.jp), and contained a "strong protest" against Koizumi's visit to the Shinto shrine, which honors Japan's war dead.
The site was hacked around 2 p.m. Monday, bureau officials said.
The police on Wednesday began investigating the incident as a suspected violation of a law against unauthorized computer access.
Diplomatic relations between China and Japan have been strained by a set of new history textbooks, bilateral trade sanctions and Koizumi's visit to the shrine Aug. 13 in the face of protests from China.
The shrine is considered controversial because 14 Class A war criminals are among those honored there.